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Simplified Science Notes

Class IV Science Notes

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All the organs of human body work in co-ordination.

Various human organs are:

Liver, lungs, heart and brain e.t.c

Central part of human body is brain. It controls and directs all parts of the body.

Adult human has approximately 1.4 Kg of brain.

If our brain gets wound, it can never heal as it does not have growth system in itself.

The shape of stomach is  “J” letter like.

Digestion of food starts from mouth and is completed in large intestine.

Ulcer is wound in stomach caused by over eating.

Carbonated drinks help in digestion of food by speeding up the process of digestion.

In every human’s mouth, there are two sets of teeth.

A. Initial or milk teeth also known as primary teeth. The number of primary teeth is 20. These start growing at the age of 3 years.                                

B. An adult has 32 teeth which are known as permanent teeth.            

Elephants have large years that help it to regulate its body temperature.

African elephants have large ears as compared to Asian elephants.

Nose has two openings called nostrils. With the help of these nostrils, nose takes in outer air (Oxygen) and send it to the lungs. It also exhales the bad air (Carbon dioxide)  from nose and leaves it into surroundings.

Nose filters,warms and moistens air with the help of hair .

Lungs are respiratory organs and are two in numbers. These are located in the chest (Thorax).

Lungs are covered in ribs.

Oxygen is first passed into the wind-pipe called tracea. Tracea conducts inhaled air into lungs through its tubular branches called bronchi. The bronchi then divides into smaller branches (bronchioles).

Lungs absorb inhaled oxygen and exhale carbon dioxide (CO2).

Asthma and lung cancers are the two important diseases of lungs.

Pumping station of the body is called heart.

Heart supplies  blood to all organs and body parts through arteries.

Heart is located slightly towards left side of the chest (Thorax).

It pumps about 72 times in a minute.

Skeletal muscles help us in movement.

Human skeleton and muscles work in co-ordination to provide us movement.

All bones of our body are collectively called skeleton.

There are 206 total number of bones in human.

The function of skeleton is to provide us support and protection to the body. It also protects our organs in the body.

Skull (Cranium) protects our brain whereas, ribs protect our lungs and heart.

At the time of birth, humans have 300 bones which are fused later on with human’s growth.

There are 26 bones in our foot and 27 bones in each hand.

A place in our body where two bones join together is called “joints”.

There are approximately 639 muscless in our body.

Outer layer of human body is known as skin.

Skin is the largest organ of our body because it covers all the body.

The thickness of body’s  skin is about 2mm.

Living organisms are :

 (a)  Plants       (b) Animals

All living organisms require :

(a) Air  (b) Water    (c) Light  (d) Food

The characteristics of parents transferred to its offspring is known as  hereditary.

The changes which occur in living organisms from their birth to the complete mature animal or plant is called “Life Cycle”.

Life cycle of a butterfly is as follows ;

The Life cycle of bee is :

The life cycle of frog is :

The life cycle of green bean plant :

Food provides us energy and nutrients which are necessary or essential for our growth and health.

 Following are essential groups of food:

1. Starch (Carbohydrates)    2. Protein   3. Fats   4.  Minerals   5. Vitamins

Carbohydrates provide us quick source of energy.

Minerals are obtained from vegetables, fruits, grain, meat and sea food.They provide us growth for body.

Vitamins are found in fruits and vegetables. They protect us from various diseases.

Proteins are known as body making food.

They provide us growth and maintenance to our tissues.

Milk, meat, eggs and pulses are rich source of proteins.

Fats are found in oil, butter e.t.c. They provide us energy and warmth.

Fats give more energy than proteins and carbohydrates.

Vitamins help our body in working properly.

Minerals are essential for improvement and growth of our body. Our body needs 21 minerals;

Calcium,Nitrogen,carbon,Sulphur,Phosphprous e.t.c


Living things depending on living and non living  things for their survival. These things are known as component of the ecosystem.

The surroundings of the living things which include living and non living things is known as ecosystem.

Biotic components include :  1. Plants      2. Animals 

Abiotic components of the ecosystem are :  1. Sun  2. Water  3. Air   4. Soil

According to consumption of food, animals fall into three categories :

1. Herbivores: They depend upon plants for their food consumption.

2. Carnivores: They depend upon animal flash.

3. Omnivores: They depend upon both plants and animals.

Goat is a herbivores, cheetah is carnivores and peacock and humans are omnivores.

Food chain is distributed into three types :

1. Producer: - Plants are producers. They get energy from sun and this energy helps in preparation of food.

2. Consumers :

 (a) Herbivores: - These are primary consumers and they eat plants, fruits and vegetables. Eg.       Goat and birds

 (b) Carnivores are secondary consumer. They eat primary consumers. Cat is secondary consumer as it depends upon primary consumers. Eg. Cat eats rats and birds.

(c) Tertiary consumer: - They eat primary and secondary consumers. Eg    wolf.

Omnivores eat producers and consumers.

3. Decomposers:- They decompose the dead bodies of producers and consumers and make the essential elements available for the soil.

Humans are omnivores.

Order of food chain is :  Producer ----------→ Consumer ----------→ Decomposer

Anything which has mass and occupies a space is called matter.

There are three states of matter:  (1) Solid        (2) Liquid      (3) Gas

Solids are hard in nature. They have fix shape and definite volume. They are not compressed by pressure.

Anything which occupies space is called volume.

Volume = Length × Width × Height

The unit of volume is cubic centimetre (cm3).

Liquid does not have shape of its own. It acquires the shape of container in which it is placed.

Gas has neither shape nor fixed volume. It can be compressed due to large space between its molecules.

All states of matter are inter convertible that means they can be converted into one another.

Solids,liquids and gases mix with one another to form mixture.

Air, drinking water, sea, sharbat etc are mixtures.

Solution is also a homogenous mixture.

Things which dissolve in water are called soluble. Eg .  Sugar and salt.

Things which do not dissolve in water are called insoluble. Eg . Sand particles.

Degree of hotness or coldness of a body is called temperature.

It is measured in thermometer.

Heat is the form of energy which flows from high temperature to low temperature.

Heat is measured in joules and calories. These are the S.I units of heat.

Clinical thermometer is used to measure body temperature. It has mercury inside it.

Laboratory thermometer has alcohol inside it.

There are various scales to measure temperature :

1.Fahrenheit (  ̊F)        2.Celsius or Centigrade (  ̊C)

Freezing point in Fahrenheit scale is 32̊ ̊F.

Boiling point in Fahrenheit scale is 212 ̊F.

Freezing point in Celsius scale is 0  ̊C.

Boiling point in Celsius scale is 100  ̊C.

Human body temperature is 98.6  ̊F or 37  ̊C.

In laboratory thermometer lowest point is -10  ̊C and highest point is 110  ̊C.

In clinical thermometer it is up to 42  ̊C.

Pulling or pushing of a body is called force.

Force can change the direction of things or body.

Force also changes shapes of body.

Speed = distance/time   (Distance covered by a body with respect to time is called speed).

The unit of speed is m/s  or meter per second.

Sound is also a form of energy. It is measured in the unit of decibels.

If the intensity of a sound is about 135 decibels, it is called a noise .

A thing or matter from which matter passes is called medium.

Speed of sound is fastest in solids because solid things are dense and tightly packed and their particles are close to one another and they help sound in passing through.

Sound does not travel in vacuum as space is vaccum therefore, we can not listen to explosions and their sound on earth.

Noise is known as unpleasant sound.

Sound is produced through vibrations.

Substances which conduct electricity are known as conductors and those substances which do not conduct electric current are called non conductors.

Everything of this world is matter. Matter is itself made of small  building blocks known as atom.

Atom has three sub-atomic particles :   1. Electron (-)     2. Proton (+)      3. Neutron (no charge).

Electric current is flow of electrons or negative charges.

LEDs ------- Light Emitting Diodes.

Magnet attracts iron (Fe) , Cobalt (Co) and Nickel (Ni).

Coins are mostly made of nickel element.

Magnet has two Poles North and South poles.

Similar poles repels each other whereas, dissimilar poles attract each other.

Earth is also a large magnet. It has its own poles.

        Magnetic properties of a magnet can be diminished by :        

1. Breaking magnet    2. Heating magnet

Permanent magnetism that can hold their properties for long time.

Temporary magnetism by  :

Making solid, Fe,Co and nickel close to the magnet and by rubbing it.

Earth is the 3rd planet of our solar system.

Earth is round or oval shaped.

Earth moves from west to east.

Due to rotation of earth days are converted into nights.

It completes its rotation in 24 hours.

Mercury planet is closest to sun.

Earth takes 365 days and 6 hours to complete revolution.

Revolution of earth causes changes in seasons.

 

Done with reading? You would want to assess your learning. For that, We have prepared multiple Mock Tests. 


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